1. Technical Field
The technical field relates to a method for preparing polyarylene sulfide.
2. Description of the Background Art
Polyarylene sulfide (PAS), specifically polyphenylene sulfide (PPS), is a material with good mechanical properties and excellent thermal and chemical resistance compared to metals of the electronic and automobile industry due to its low density. PAS is also useful in spinning fibers of filters, connectors, coating material, and electronic components. Conventionally, the preparation of PAS is formed by reacting p-dichlorobenzene and sodium sulfide as monomers. A massive byproduct of alkali metal halide resides in the PAS resin, so the PAS resin needs some purification steps. However, purification by removal of the salty waste increases the production cost, degrades the quality, and decreases the efficiency of the production of PAS resin.
JP 07-304872 A discloses the preparation of a polysulfonium intermediate by reacting methyl 4-(phenylthio)phenyl sulfoxide in trifluoromethanesulfonic acid and then demethylating the polysulfonium intermediate with pyridine to obtain a neutral PAS resin with pyridinium salt as a byproduct. This reaction scheme is illustrated below.

However, a salty waste byproduct such as pyridinium salt is disadvantageous. Specifically, a salty waste byproduct results in increased cost due to the additional steps needed to purify the PAS resin. In addition, the salty waste byproduct is not environmentally friendly. Therefore, an industry-wide need exists for a method of preparing a polyarylene sulfide without a salty byproduct.